your best bet would be a hilux diffs, if LC40 they are not centered. sa hilux off center ang front only just like the configuration of the terrano transfer case. dont know lang if on the left or on the right ang transfer case output.

but if i were you stay with the stock terrano underchassis na lang. less modifications the better, less headaches to be encountered on the trail. and besides IFS front is not that bad off road.